Long-tube heatless concentrator



FIG. 1 is a front elevational view of a long-tube heatless concentrator, showing my new design;

FIG. 2 is a side elevational view thereof, turned 90° with respect to FIG. 1;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof; and

FIG. 5 is a perspective view thereof. 

The ornamental design for a long-tube heatless concentrator, as shown and described. 